U.S. Pat. No. 8,613,813, is directed, in certain aspects, to a method of rapidly heating and shaping a metallic glass using a rapid discharge of electrical current, where a quantum of electrical energy is discharged through a substantially defect-free metallic glass sample having a substantially uniform cross-section to rapidly heat the sample to a processing temperature between the glass transition temperature of the metallic glass and the equilibrium melting temperature of the metallic glass forming alloy, and then applying a deformational force to shape the heated sample into an article, and then cooling said sample to form a metallic glass article.
U.S. Patent Publication No. 2013/0025814 is directed, in certain aspects, to a method and apparatus of injection molding metallic glass articles using the RCDF method, including an insulated feedstock barrel, or “barrel,” that is used to electrically insulate and mechanically confine the heated feedstock. Each of the foregoing patent publications is incorporated herein by reference in its entirety.
One class of material that has been explored is toughened ceramics. Examples of proposed ceramic barrel materials include Macor, yttria-stabilized zirconia or fine-grained alumina. Ceramics are electrically insulating and chemically very stable up to high temperatures, and when properly processed they may have substantial toughness and machinability. But ceramics are generally relatively expensive materials, and the various processes used to toughen them are complex, labor intensive, and add significantly to the overall cost. Machining of ceramics is generally hard, time intensive, and requires expensive tooling. Moreover, the requirement for split-barrel design further complicates the machining process and adds to the overall cost. Therefore, even if an extended tool life is achieved with toughened ceramics enabling multiple RCDF cycles, owing to the high overall cost, the cost per RCDF cycle with ceramic barrels can still be prohibitively high for many applications.